Sept. 12 (UPI) -- Ten Democratic presidential candidates are set to participate in the third round of primary debates in Houston Thursday night, about half the field who appeared in the first two this summer.
The debate will be staged at Texas Southern University and will be moderated and broadcast by ABC News and Univision, beginning at 8 p.m. EDT.
Unlike the first two debates in Miami and Detroit, the Houston event will feature all qualifying candidates on one stage, on one night. The last two were spread over two nights and a random draw determined who debated on which night.
The candidates who will appear Thursday night are former Vice President Joe Biden, Massachusetts Sen. Elizabeth Warren, Vermont Sen. Bernie Sanders, California Sen. Kamala Harris, South Bend, Ind., Mayor Pete Buttigieg, businessman Andrew Yang, New Jersey Sen. Cory Booker, former Texas Rep. Beto O'Rourke, Minnesota Rep. Amy Klobuchar and former Housing and Urban Development Secretary Julian Castro.
Thursday will be the first time Biden and Warren, considered among the front-runners, share the stage.
Candidates still in the race who did not qualify for Thursday's event are Colorado Sen. Michael Bennet, New York City Mayor Bill de Blasio, Montana Gov. Steve Bullock, former Maryland Rep. John Delaney, Hawaii Rep. Tulsi Gabbard, Ohio Rep. Tim Ryan, former Pennsylvania Rep. Joe Sestak, author Marianne Williamson and San Francisco billionaire Tom Steyer.
The change is the result of more stringent qualifications set by the Democratic National Committee, which required candidates to receive at least 2 percent support in at least four national polls, or polls conducted in the early-voting states of Iowa, New Hampshire, South Carolina and Nevada. They were also required to garner grass-roots fundraising from at least 130,000 total unique donors and have a minimum of 400 unique donors per state in 20 or more states.
Some of the chief topics expected Thursday night are the trade conflict with China, climate change, healthcare and gun violence.
Since the last debate in Detroit, several candidates have unveiled plans for gun control, which coincided with multiple new shooting attacks in the United States.
O'Rourke's plan calls for mandatory gun buybacks and universal sale checks, while Yang proposed to end the influence of lobbyists and implement "common sense" gun reform. Buttigieg proposed a $100 billion investment in mental health. Castro issued a plan to "disarm hate" by addressing firearms and white nationalism.
"We need a president who actually cares about this and will bring people together instead of driving them apart," Castro said at a gun violence forum in Iowa last month.
"We need background checks. Let's just start with that," Klobuchar added. "It's not about everyone needs to stop selling guns. But we absolutely need to have checks and balances on it."
Biden addressed the issue at the Iowa State Fair, in a state that will hold one of the first Democratic primaries in February.
Candidates have also spent time outlining how they plan to protect the environment and scale back climate change.
Buttigieg and Harris unveiled their plans ahead of a CNN Town Hall on climate change last month, while Castro proposed directing $10 trillion over the next decade to building a clean-energy economy. Booker revealed a plan to spend $3 trillion to transition to a 100 percent carbon-neutral economy and Sanders introduced a $16 trillion proposal to rely exclusively on renewable energy by 2030 and de-carbonize the economy by 2050.